SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20077f7f0eeb7de16fe933d52f13e76be5e1e3e48007135f4e844b98f916215d' 
  AND token = 'Quw0dx/gUm8a+InPmTCj09oN2UNA+bDor7H7xz3UkhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}